Ok, this is complete BS. Have had my windows client in this for months now... no fix. Now same happened to Mac client! And with that I got a hint WTF is problem

It worked fine until I connected steam integration. After that, no luck, no start... so.. basically steam connection kills this? I have large library in steam, so that might be causing it. but it is kinda of unforgivable, that this bug have been around now months.. well do not expect me to buy any games in GOG store, until you start to do something for the client, so it does not die to cycle, where only cure you advice is "clean install".

But here is a hint: It dies on adding steam integration. So do some error check there that client DROPS THE INTEGRATION RATHER THAN HANGS IT SELF COMPLETELY. Duh.